Battery management system and driving method for the system

• US 20110095765A1
• Filed: 07/21/2010
• Published: 04/28/2011
• Est. Priority Date: 10/19/2009
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH, Samsung SDI Company Limited
• Original Assignee: Robert Bosch GmbH, Samsung SDI Company Limited
• Inventors: Boehm, Andre, Tae, Yongjun
• Granted Patent: US 8,587,256 B2
• Time in Patent Office: Days
• US Class Current: 324/434
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/385 Arrangements for measuring battery or accumulator variables for monitoring G01R31/382
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A BMS and driving method, the BMS including a sensing unit sensing voltages and currents of battery cells and an MCU determining an SOC of the battery cells and controlling charging and discharging based on cell voltages and currents of the battery cells, wherein the MCU includes an SOC measurer measuring first SOCs and, after a predetermined duration, second SOCs of the battery cells; and a controller determining whether a first difference value between a maximum second SOC value and the second SOCs of each battery cell is greater than a first reference value or determining whether a second difference value between the first and second SOCs of respective battery cells is greater than a second reference value, and determining which battery cell is shorted when the first difference value is greater than the first reference value or when the second difference value is greater than the second reference value.

Claims

1. A battery management system, comprising:

a sensing unit, the sensing unit sensing cell voltages and cell currents of a plurality of battery cells; and

a Main Control Unit (MCU), the MCU determining a State of Charge (SOC) of the plurality of the battery cells and controlling charging and discharging based on the cell voltages and cell currents of the plurality of the battery cells,

wherein the MCU includes;

an SOC measurer, the SOC measurer measuring first SOCs of each of the battery cells and, after a predetermined duration, second SOCs of each of the battery cells, and

a controller, the controller determining whether a first difference value between a maximum value from among the second SOCs of the plurality of battery cells and the second SOCs of each battery cell is greater than a first reference value or determining whether a second difference value between the first and second SOCs of respective battery cells is greater than a second reference value, and determining which battery cell among the plurality of the battery cells is a shorted battery cell when the first difference value for the battery cell is greater than the first reference value or when the second difference value for the battery cell is greater than the second reference value.

2. The battery management system as claimed in claim 1, wherein the MCU further includes a data storage, the data storage storing the first SOCs, the second SOCs, the first reference value, and the second reference value.

3. The battery management system as claimed in claim 1, wherein the controller is configured to determine whether the second difference values are greater than the second reference value if the first difference values for all the battery cells are less than the first reference value.

4. The battery management system as claimed in claim 1, wherein the controller is configured to determine whether the first difference values are greater than the first reference value if the second difference values for all the battery cells are less than the second reference value.

5. The battery management system as claimed in claim 1, wherein:

the MCU is configured to transmit information regarding the shorted battery cell to an Engine Control Unit (ECU), and

the ECU is configured to display the information regarding the shorted battery cell on a display device.

6. A driving method for a battery management system, the driving method comprising:

determining battery cell States of Charge (SOC) by determining first SOCs of each of a plurality of battery cells and, after a certain duration, determining second SOCs of each of the battery cells;

comparing difference values with reference values through determining whether a first difference value between a maximum value from among the plurality of second SOCs of the battery cells and the second SOC of each battery cell is greater than a first reference value, or determining whether a second difference value between the first and second SOCs of each of the battery cells is greater than a second reference value; and

determining a battery cell from among the plurality of battery cells to be a shorted battery cell when the first difference value for the battery cell is greater than the first reference value, or when the second difference value for the battery cell is greater than the second reference value.

7. The driving method as claimed in claim 6, wherein the comparing of the difference values with the reference values includes the determining whether the first difference value between the maximum value from among the plurality of second SOCs of the battery cells and the second SOC of each battery cell is greater than the first reference value and conditionally also includes the determining whether the second difference value between the first and second SOCs of each of the battery cells is greater than the second reference value and wherein the determining whether the first difference value between the maximum value from among the plurality of second SOCs and the second SOC of each battery cell is performed prior to conditionally determining whether the second difference value between the first and second SOCs is greater than the second reference value.

8. The driving method as claimed in claim 7, wherein in the comparing of the difference values with the reference values, determining whether the second difference values are greater than the second reference values occurs on the condition that the first difference values for all the battery cells are less than the first reference value.

9. The driving method as claimed in claim 6, wherein, the comparing of the difference values with the reference values includes determining whether the second difference value between the first and second SOCs of each battery cell is greater than the second reference value and conditionally also includes determining whether the first difference value between the maximum value from among the plurality of second SOCs of the battery cells and the second SOC of each battery cell is greater than the first reference value and wherein the determining whether the second difference value between the first and second SOCs of each battery cell is performed prior to conditionally determining whether the first difference value between the maximum value from among the plurality of second SOCs and the second SOC of each battery cell is greater than the first reference value.

10. The driving method as claimed in claim 9, wherein in the comparing of the difference values with the reference values, determining whether the first difference values are greater than the first reference values occurs on the condition that the second difference values for all the battery cells are less than the second reference value.

11. The driving method as claimed in claim 6, further comprising issuing an alert on the shorted battery cells by displaying information regarding the shorted battery cells.